Self Assessment Deadline 31 January 2027: Every Date, Penalty and Fix for 2025/26

One table, every date that matters for the 2025/26 tax year (6 April 2025 to 5 April 2026). The online filing, paper filing, coding-out and balancing payment deadlines fall at 11:59pm on the day shown; payments on account are due by midnight.

The online and paper deadlines come from GOV.UK (GOV.UK); the payment dates and payments on account from HMRC's payment pages (GOV.UK). If you registered after 5 October 2026, your filing date may be later than the table shows, though the tax date does not move. That is covered below.

Anyone with income or gains HMRC has not already taxed in full. GOV.UK lists the triggers: you must file if, for example, you were a sole trader earning more than £1,000 before reliefs, a business partner, owed Capital Gains Tax, or owed the High Income Child Benefit Charge outside PAYE (GOV.UK).

Untaxed income is the wider net. Rent from property or land, tips and commission, savings interest, dividends, foreign income, and any taxable UK income if you are not UK resident can all require a return. GOV.UK sets no general £1,000 threshold for that list. Four groups need particular care, and each has its own traps.

• Foreign nationals living in the UK. A UK resident with foreign income or capital gains usually needs a return. The narrow exception is where the only foreign income is dividends, total dividends (UK included) are under the £500 dividend allowance, and there is nothing else to report (GOV.UK). See tax returns for foreign nationals.
• Recent arrivers under the FIG regime. A UK resident normally pays UK tax on foreign income unless eligible for FIG relief, and the relief comes only through a claim on the return. A qualifying new resident is in one of their first 4 years of UK residence after at least 10 consecutive tax years of non-UK residence (GOV.UK). 2025/26 was the regime's first year, so these are the first FIG returns ever filed. See FIG regime tax returns.
• UK residents with overseas income. Most foreign income, such as overseas interest, dividends, pensions and property income, goes in the foreign section of the return, the SA106 (foreign employment income goes on the Employment pages). There is a shortcut for small amounts: if your only foreign income was untaxed foreign interest of up to £2,000, it can go in box 3 of the main return instead. If that interest and foreign dividends of up to £500 are your only foreign income, the dividends can go in box 6 where you claim deduction relief, unless your total UK and foreign dividends exceed £500 and you can claim deduction relief or Foreign Tax Credit Relief, in which case the Foreign pages are needed (GOV.UK). FIG claimants cannot use that shortcut: all their foreign interest and dividends go on the SA106, whatever the amount (GOV.UK). See reporting overseas income.
• Non-residents with UK rent. If you live abroad you usually have to file if you rent out UK property, work for yourself in the UK, have taxable UK savings interest, or have other untaxed UK income (GOV.UK). UK rent stays chargeable to UK tax even for a non-resident landlord, and no double taxation convention transfers that right (GOV.UK). HMRC approval to receive rent without tax deducted is not an exemption: the income still goes on the return. See non-resident landlord returns.

Online gives you three more months. Not everyone can use HMRC's free service to get them. Paper returns for 2025/26 must reach HMRC by 11:59pm on 31 October 2026, and online returns are due by 11:59pm on 31 January 2027 (GOV.UK).

The SA109 is the problem. For 2025/26 it is titled "Residence and foreign income and gains (FIG) regime etc", and it is completed by non-residents and by UK residents who want to make a FIG claim, a Temporary Repatriation Facility election, a split-year claim or an Overseas Workday Relief claim, among others (GOV.UK). Non-residents cannot use HMRC's online services to report their income (GOV.UK), and filing the SA109 online needs commercial software or a professional agent (GOV.UK).

That leaves three routes: paper by 31 October 2026, commercial software that supports the SA109 by 31 January 2027, or an agent by 31 January 2027. Non-resident landlords face the same choice. They complete the residence section and the SA105 property pages, and cannot use HMRC's online services (GOV.UK). Our guide to why the SA109 cannot be filed online has the background, and the DIY versus accountant comparison sets out what each route costs.

Registering from abroad has its own friction. On the route for people who are not self-employed, you cannot register online if you do not live in the UK; the alternative is form SA1, printed and posted (GOV.UK). After postal registration the UTR usually arrives in 15 working days, or 21 days if you are abroad, and can take longer in busy periods. An agent can register a client on the SA1 with a postal address outside the UK (GOV.UK).

Horizon files the SA109 as your agent. A Non-Resident and Expat Tax Return is £550 fixed; complex returns start from £750. Book a free 30-minute clarity call.

Register now. Late is not the same as lost. The 5 October 2026 deadline applied if you need a 2025/26 return and have never sent one, or registered before but did not need to file for 2024/25. Telling HMRC after that date could lead to a penalty (GOV.UK).

Two things change. The first is your filing date. GOV.UK's deadlines page says HMRC will send a letter or email giving a different deadline, 3 months from the date on it, and that the tax must still be paid by 11:59pm on 31 January 2027 (GOV.UK). HMRC's 2025/26 SA150 notes word it differently: online by 31 January 2027, or 3 months after the date on your notice to file if that is later (GOV.UK). Read the date on your own notice and work to that.

The second is the failure to notify penalty. It may arise if you register after 5 October and do not pay all of your tax by 31 January. It is based on the amount still unpaid, and HMRC issues it within 12 months of receiving the return (GOV.UK). HMRC's factsheet CC/FS11 sets it as a percentage of potential lost revenue: for a non-deliberate failure disclosed unprompted within 12 months of the tax being due, the range is 0% to 30%. HMRC will not charge it at all if you had a reasonable excuse, the failure was not deliberate, and you told HMRC without unreasonable delay once the excuse ended (GOV.UK).

The practical answer is short. Register immediately, and plan to pay the full 2025/26 bill by 31 January 2027 even if your notice gives a later filing date.

Pay by 11:59pm on 31 January 2027, or a penalty applies (GOV.UK). That payment covers the 2025/26 balance and, where it applies, the first payment on account for 2026/27 (GOV.UK).

Coding out is an alternative to a January payment for some taxpayers. If you already pay tax through PAYE, for example as an employee or someone receiving a company pension, and owe less than £3,000, HMRC can collect the bill through your tax code. You cannot make a part payment to get under £3,000 (GOV.UK). The return must be filed online by 11:59pm on 30 December 2026, or on paper by 31 October 2026 (GOV.UK).

Paying from abroad works by bank transfer. The payment reference is your 10-digit UTR followed by the letter K. From an overseas account, use either of these HMRC accounts (GOV.UK):

• HMRC Cumbernauld: IBAN GB62 BARC 2011 4770 2976 90, BIC BARCGB22.
• HMRC Shipley: IBAN GB03 BARC 2011 4783 9776 92, BIC BARCGB22.

Some banks charge if you do not pay in sterling, and payments from overseas may take longer than usual, so check with your bank. The money has to reach HMRC by the deadline, not merely leave your account by it. Send it in the week before, not on the day.

First-time filers often pay half as much again in January. Payments on account are advance payments towards next year's bill. Each is half of the previous year's tax, due by midnight on 31 January and 31 July (GOV.UK). You do not make them if last year's tax was under £1,000, or if more than 80% of it was paid outside Self Assessment, for example through PAYE.

A first-time filer has made no advance payments, so 31 January 2027 collects the whole 2025/26 bill plus the first 2026/27 payment on account, which is half that bill again. A £20,000 liability becomes a £30,000 January payment, with another £10,000 due on 31 July 2027. If you expect next year's income to be lower, you can claim to reduce the payments on account; our answer on payments on account explains how.

FIG claimants should budget early. A claim costs allowances including the Personal Allowance and the CGT annual exempt amount, even if the claim is for income only (GOV.UK), so UK salary, rent or gains in a claim year are taxed from the first pound. Our guide to the first FIG filing season runs the timeline month by month.

Late filing and late payment are penalised separately. The late filing schedule for a Self Assessment return is (GOV.UK):

• An initial £100 penalty, even if you owe no tax or have already paid in full.
• Once the return is 3 months late: £10 a day, up to a maximum of £900.
• Once it is 6 months late: a further 5% of the tax due or £300, whichever is greater.
• Once it is 12 months late: another 5% of the tax due or £300, whichever is greater.

Late payment penalties are 5% of the tax still unpaid at each of three points: 30 days, 6 months and 12 months. Interest is charged on top. HMRC sets late payment interest at Bank of England base rate plus 4%, so the rate moves when base rate does; check the current published rate on GOV.UK before you rely on a figure (GOV.UK).

Example 1: no tax due, return 12 months late. Someone owes nothing for 2025/26 but files a year late. The penalties are £100, plus £900 in daily penalties, plus £300 at 6 months and another £300 at 12 months, because 5% of nil is less than £300 each time. Total: £1,600, with no tax owed at all.

Example 2: £20,000 of tax, filed and paid about 7 months late. Late filing costs £100, plus £900 in daily penalties, plus £1,000 at 6 months (5% of £20,000 is more than £300): £2,000. Late payment costs £1,000 at 30 days and another £1,000 at 6 months, since the full £20,000 was unpaid at both points: £2,000. Total penalties of £4,000, plus interest on the unpaid tax. For simplicity this ignores payments on account.

Example 3: filed on time, paid 3 months late. The same £20,000 return goes in on 31 January 2027 but the tax is paid in late April. There is no late filing penalty. The late payment penalty is £1,000 at 30 days, plus interest. Filing on time is worth doing even when the money is not ready.

These illustrations apply GOV.UK's published rates to round numbers. HMRC calculates the actual charges on your own figures.

You can appeal if you had a reasonable excuse (GOV.UK). HMRC defines one as something that stopped you meeting a tax obligation for a valid reason. Relying on someone else to send your return, when they did not, may count. A payment that failed because you did not have enough money does not, and nor do finding HMRC's online system too difficult, not getting a reminder, or making a mistake on the return. Once the excuse ends, you must send the return or payment as soon as you are able (GOV.UK). For people abroad, distance and unfamiliarity with the system are not reliable excuses.

Timing is tight. You usually have 30 days from the date the penalty was issued to contact HMRC or appeal (GOV.UK). You can appeal online, or by post on form SA370 or SA371. HMRC suggests considering paying the penalty while you appeal, because if the appeal is rejected, interest runs on the penalty from its due date (GOV.UK).

31 January 2027 is also last year's deadline. A return can usually be changed within 12 months of the Self Assessment deadline, which for 2024/25 means by 31 January 2027 (GOV.UK). If your 2024/25 return left out foreign income, used the wrong residence position or missed a claim, that is the window to fix it through the normal amendment route.

One 2025/26 time limit runs later. HS266 sets 31 January 2028 as the time limit for a 2025/26 FIG claim (GOV.UK). That is not a reason to file now and claim later without thinking. A claim must be made for each amount of foreign income, from each source, and HMRC's manual says there is no automatic relief: getting the figure wrong does not invalidate a claim, but not quantifying it at all does (GOV.UK).

Each missed date has a fix. The order matters.

• Missed 5 October 2026: register now, by post on form SA1 if you live abroad and are not self-employed, or through an agent. Then pay the full bill by 31 January 2027, because the failure to notify penalty is based on what is still unpaid then.
• About to miss 31 October 2026 on paper: switch to online. Commercial software that supports the SA109, or an agent, can file by 31 January 2027.
• On PAYE and owing under £3,000: file online by 30 December 2026 to have the bill collected through your tax code.
• Past 31 January 2027: file as soon as you can. The £100 is fixed, but daily penalties start at 3 months and the 6-month penalty is at least £300. Pay as early as possible too, because interest and the late payment points run separately.
• Several years behind: the approach is different. Start with what to do if you never filed, and for undeclared UK rent, the Let Property Campaign guide.

Non-resident landlords have one more check. Under the Non-resident Landlord Scheme, tax deducted by your agent or tenant is shown on the NRL6, and you can set it against your UK liability for the same year. The NRL6 figure may not match your actual liability on the rental profits, so the return can show more to pay or, if you are eligible for the Personal Allowance, a refund. On the SA105, a non-resident landlord puts total rental income, without tax taken off, in box 20 and the tax taken off in box 21. Our non-resident landlord tax guide covers the scheme and the NRL forms in full.

Horizon UK Tax Solutions is a Chartered Tax Adviser practice, founder-led by Jordan Onraet-Wells and based in London. Over 10 years of experience, including 7 at a Big Four firm. Rated 5.0 on Google from 19 reviews, and AML-supervised. Everything is handled remotely, for clients across six continents, with direct access to the adviser all year.

We file as your authorised agent with HMRC, including the SA109 pages that HMRC's free online service cannot file. That covers FIG claims, Overseas Workday Relief, split-year claims, SA106 foreign income and Foreign Tax Credit Relief, non-resident landlord returns and NRL1 applications, and the separate 60-day CGT return. Where another country needs an in-country filing, we lead on the UK position and coordinate vetted specialists there. We do not file other countries' returns.

The fees are fixed and published. Standard Personal Tax Return £350. Non-Resident and Expat Tax Return £550. Complex Personal Tax Return from £750, for multiple income streams, investments, trusts or complex structures. The fee is agreed in writing before work starts. We do not bill by the hour.

A free 30-minute clarity call. A fixed quote and engagement. Identity and address checks before work starts, as anti-money-laundering rules require. Documents uploaded to a secure client portal. We prepare the return, you review and approve it, and we file it and confirm what to pay and when. You stay legally responsible for your own tax, which is why you check and confirm the return before it goes in (GOV.UK). Once you are registered, you give us authority online or on form 64-8 (GOV.UK).

Book a free 30-minute clarity call, or try the fee estimator first. Every return type we handle for this deadline is on the 31 January tax returns hub.